In the United States there are currently no regulations regarding the sterilization requirements of topical antiseptic solutions. Therefore, antiseptic solutions currently sold in the United States generally do not undergo a sterilization process. In other jurisdictions, however, such as European Union (EU) countries, some degree of sterilization is required. A known antiseptic solution containing 2% w/v chlorhexidine gluconate in 70% v/v isopropanol in water (i.e., an alcoholic solution), manufactured by CareFusion Corp., is sterilized for EU countries using a known sterilization method.
It is the industry belief that high temperature sterilization is not suitable due to the expected degradation. See, for example, Kelly M. Pyrek, “Sterility of Antiseptic Products: FDA Investigates, Deliberates on Potential Recommendations,” Infection Control Today (July 2013): 24-26 and Block, Seymour S. Disinfection, Sterilization, and Preservation. Philadelphia: Lippincott Williams & Wilkens, 322-323. 2001.
A known method of sterilization involves heat treating glass ampoules containing the chlorhexidine gluconate alcoholic solution in a convection oven at 76-80° C. for 24-31 hours. It was believed that relatively low temperature and relatively long processing time is necessary to sufficiently sterilize the antiseptic alcoholic solution without overly degrading the antimicrobial molecules, thereby avoiding reducing the concentration and purity of the chlorhexidine gluconate contained therein as an antiseptic. Applicant's copending U.S. application Ser. No. 14/150,488 describes an alternative method for sterilizing an alcoholic solution, which is hereby expressly incorporated by reference herein in its entirety.
However, there is no known method of sterilizing an aqueous antiseptic solution that affords a sterile solution without overly degrading the antimicrobial molecules. Thus, there is an unmet need in the art for a method of sterilizing aqueous antiseptic solutions.